【作者】 楼金其；

【导师】 邱延峻； 徐宏；

【作者基本信息】 西南交通大学 ， 建筑与土木工程， 2004， 硕士

【摘要】 软土地基由于土颗粒细，孔隙比大，含水量大，孔隙中的水不易排出，所以在这类地基上修建工程主要问题是地基强度低，受荷后变形大，引起构筑物下陷量大，构筑物极易失稳。如果不对软基进行处理或采取的措施不当，不仅加大工程量，花费过高的工程费用，拖长工程建设期限，甚至可能会造成工程失败。 本论文结合新长铁路软土地基处理(袋装砂井，粉喷桩)和现场施工、变形监测，开展路堤荷载作用下软基的工程特性分析及处治效果等的理论与实践的研究，重点研究以下内容： 1．对新长铁路嘎梁河以东DK183+087～DK183+303段进行工程地质勘察工作(包括地质钻探、土工试验和静力触探试验等)，获得了区域地质概况、土体结构、土体(尤其是软土)的物理力学性质指标，揭示了该路段软土的特性。 2．以岩土工程静力分析有限元程序PDSS2000为工具，基于平面变形，空间渗流(Plane Deformation，Spatial Seepage，缩写为PDSS)理论，定量分析了路堤荷载作用下袋装砂井地基、粉喷桩复合地基的变形、孔压等力学响应。 3．详细介绍了袋装砂井、粉喷桩处治软土地基的优缺点，注意事项及完整施工过程。 4．对新长铁路四个断面进行了现场施工中的变形观测，分析了其施工过程中出现较大变形的现象及其原因。 通过上述四个方面的纵横向对比分析与讨论，对袋装砂井、粉喷桩处治软土地基等问题会有一个更全面、更深入的认识，并可得出一些有意义的结论，可供铁路设计部门及施工单位作参考。更多还原

【Abstract】 Embankments constructed over thick soft cohesive deposits are an important part of civil engineering insfrastructure. Stability, the doformations and time required for consolidation are the major concerns in the design and construction of embankments over soft foundations that typically have both low shear strength and low hydraulic conductivity. Deformatin performance in soft ground under embankment loading has been a great concern for railway engineers.The following work is carried out combined with the Xin-chang railway comnstruction:l.The behaviour of embankments over soft foundation using field case to investigated the behaviour of soft soil.2. The finite element method has proved to be powerful technique for use in the evaluation of embankment behaviour. Based on the plane deformation spatial seepage theory, finite element program PDSS2000 was conducted to interpret the field behaviour of reinforced embankments and carry out sensitivity studies.3.The advantage, disadvantage and some advice are detailed illustrated using PVC and compose ground.4.The field observation was taken during construction and the cause of large deformaion was discussed.Major conclusions drawn from this study can be beneficial to the structural design, supervision, maintenance, and rehabilitation of embankment engineering for raiways. And offer some useful thoughtways, which are referenced and valuable for embankent engineering design over thick soft ground in future.更多还原